Allyl dialkylthiolcarbamate nematocides



United States Patent 6 Claims. (Cl. 167-22) This application is acontinuation of Ser. No. 433,802 filed Feb. 18, 1965, said Ser. No.433,802 being a division of Ser. No. 642,924 filed Feb. 28, 1957, and acontinuation of Ser. No. 319,629 filed Oct. 7, 1963, said three priorapplications being now abandoned.

This invention relates to bilologically active thiolcarbamates and tomethods of pest control employing them. The invention includes methodsof destroying or controlling undesired vegetation, fungi, and nematodesand relates to biologically active compositions useful for suchpurposes. More particularly, it relates to methods of destroying orcontrolling undesired vegetation and other pests which comprise applyingthereto an effective concentration of a toxic ester of thiolcarbamicacid.

General objects of the invention are to provide compositions which aretoxic to living plants, nematodes, fungi, or other pests or combinationsthereof and to provide methods for their use to accomplish variousdesirable ends. Still another object is to provide methods fordestroying nematodes. Other and further objects will be apparent fromthe detailed description which follows.

A method of destroying or controlling pests according to this inventioncomprises applying thereto an effective concentration of a toxic esterof a thiolcarbamic acid. It has been found that the biologically activethiolcarbamic acids those conforming to the structure where R is anorganic amino substituent having the nitrogen atom connected directly tothe carbonyl radical and to two other carbon atoms and where Rrepresents an open-chain unsaturated group comprise an especiallyvaluable class. The valences of the amino substituent represented by Rare preferably satisfied by lower alkyl groups; but if the chain isinterrupted by oxygen or sulfur, compounds having higher molecularWeights maintain high biological activity. Moreover, heterocyclic aminosubstituents are especially efficacious. The unsaturated grouprepresented by R is preferably an alkenyl group either unsubstituted orsubstituted by halogen, although the presence of halogen servessignificantly to increase the bilogical activity. Typical examples of Rcomprise cisand trans- 2,3-dichloro-2-butenyl, 3-chloro-2Fbutenyl,2-chloroally, 2- bromoallyl, 3-c'nloroallyl, cisandtrans-2,3-dichloroallyl, 3iodoallyl, 3-iodo-2-butenyl,2,3-diodo-2-butenyl, 2- fiuoro-3-chloroallyl, vinyl, allyl, Z-butenyl,4-chloro-2- butenyl, 2-iodoallyl, 3-bromoallyl, and 2,3-dibromoallyl.These are believed to be a new class of compounds.

The new toxicants may be applied conveniently in the form of a spraycontaining the active ingredient in a concentration within the range of0.l%-10.0% by weight. At concentrations within the range of 35-100pounds per acre, the new compounds are soil sterilants and destroy allplant life as well as destroying some animal pests.

Although most thiolcarbamates are isoluble in water they are soluble inorganic solvents. Most of them are soluble in acetone, chloroform, ethylalcohol, ethyl acetate,

Patented May 7, 1968 benzene, ether, and heptane. The esters may bedispersed directly in water or a solution in an organic solventemulsified in aqueous medium by the aid of a dispersing agent. Asdispersing and wetting agents, the-re may be employed soft or hardsodium or potassium soaps, alkylated aromatic sodium sulfonates such assodium dodecyl benzene sulfonate, or an amine salt of dodecyl benzenesulfonate, or an amine salt of dodecyl benzene sulfonic acid, alkalimetal salts of sulfated fatty alcohols, ethylene oxide condensationproducts of alkyl phenols or tall oil and other dispersing and wettingagents.

As explained above and as will be hereinafter illustrated in greaterdetail, the substitutents which are attached to the nitrogen of thenucleus can be varied considerably. While the relationship betweenbiological activity and structure is, to say the least, obscure, somegeneralities derived from study of a large number of differentstructures appear to be valid. The presence of hydrogen on the nitrogenaffects activity profoundly. The compounds contemplated here have nohydrogen attached to the nitrogen. Aryl groups, as for example phenyl,alicyclic groups, as for example cyclohexyl, and alkyl groups, as forexample benzyl, are less desirable; and in any event, not more than oneradical should be selected from these types. Unsaturated radicals arecontemplated, as for example cyclohexenyl, alkenyl, andhalogen-substituted alkenyl. More than one halogensubstituted radical isusually not beneficial, and this includes the ester group as well. Inother words, if the ester radical is halogen-substituted alkenyl, thepresence of a second radical of this type on the nitrogen does notusually increase effectiveness. Similarly, with an unsubstitutedalkenylgroup as the ester radical and a halogen-substituted alkenyl groupattached to the nitrogen, the presence of a second halogen-substitutedalkenyl group would be expected to decrease effectiveness.

While the alkyl thiolcarbamates examined had only a low order ofactivity, the unsaturated esters proved to be very valuable compounds.Cyclic groups, as for example cyclohexenyl, are desirable, but aromaticesters are not included. By nonaromatic is meant radicals which do notcontain an aromatic ring linked directly to the sulfur. Thiazolylesters, as for example 5-acetyl4-methyl- 2-thiazolyldiethylthiolcarbamate, are useful, these compounds being characterizedby contact phytotoxicity to broadleaves.

Controlling harmful and unwanted parasites present in the soil, such asnematodes, is an important problem of considerable complexity. Some ofthe new compounds are effective for this purpose, notablyhalogen-substituted alkenyl esters of dimethylthiolcarbamate, as forexample 2-chloroallyl and 2,3-dichloroallyl dimethylthiolcarbamate. Inorder to be an effective toxicant, a compound must be able to penetratethe normally impervious outer covering of the worm as well as theenclosing membranes of the larvae and eggs and to interfere with somevital function of the organism. While the exact mechanism of destroyingthe soil worm life is not fully understood, it is believed that theeffective toxicants destroy or reduce to a low level the effectivenessof vital enzymes. A compound which is effective must be one that willremain in the soil in contact with the undesirable worm life for asufiicient period of time to effect the penetration of the worm and todestroy it by one means or another. To accomplish this result, it isnecessary that the toxicant resist the destructive action of soilbacteria, be capable of Wetting or penetrating the parasite, possess asubstantial Water dispersibility, be capable of ready mixture with thesoil,

and possess a sufficiently low vapor pressure so that it does notevaporate before its destructive action is accomplished. Since theexacting requirements of any practical agent cannot be recognized bymethods other than by test, it is necessary to observe the effectivenessof chosen compounds against the life cycle of the parasite.

Nematocidal activity was demonstrated by preparing a suspension of thenematode Panagrellus r edivivus in water and observing through amicroscope the motility of the organisms in the presence of 0.1% of thetest material. The nematode in aqueous suspension will flex its body ata regular rate; and as the nematocide takes effect, the rate of flexingis decreased until death of the parasite occurs. In this experiment thecontrol containing no added toxicant showed undiminished activity after24 hours, whereas complete destruction of the nematode was effected with2-chloroallyl dimethylthiolcarbamate. Although less effective, activityas contact nematocides was exhibited by 3,3-dichloroallyldiethylthiol-carbamate, 2,3- dichloroallyl diethylthiolcarbamate,2-bromoallyl diethylthiolcarbamate, and allyl dimethylthiolcarbamate.

In another experiment sterilized soil was infested with nematodes(Meloidogyne sp.) and different portions treated with solutionscontaining concentrations of 0.1 and 0.0l% by weight of 2-chloroallyldimethylthiolcarbamate. The treated soil was allowed to stand for aweek, then two-week old tomato plants were transplanted in the test soiland also in untreated, heat-sterilized soil. The plants were allowed togrow for two months, then were harvested, the roots washed and examinedfor evidence of infection. Comparison to the untreated controls gave thephytotoxicity of the compound. The results showed no nematodeinfestation and no phytotoxi-city in both the untreated and treatedsoils.

The nematocidal compositions attack the soil phase of the life cycle ofnematode parasites which infest animals. Treating barnyards, chickenpens, stables, and other infested areas destroys eggs and infectivelarvae of many parasites which infest animals. Moreover, thecompositions are effective for the control of nematodes in theirenvironment which includes bodies of animals. They are toxic to otherworms such as fiukes and tapeworms.

In the use of 2-chloroallyl dimethylthiolcarbamate as a nematocide orsoil fumigant, the active compound, diluted or undiluted, may be appliedto the soil at rates of 10 to 500 pounds per acre. The preferredapplication for treating soils of average nematode infestation will befrom 25 to 100 pounds per acre. Formulation may contain dispersantswhich aid uniform distribution.

Several methods are available for the preparation of thiolcarbamateesters. The halide corresponding to the desired ester is condensed withan alkali metal thiolcarbamate in one method. The alkali metalthiolcarbamates are available from reaction of carbonoxysulfide withamines in the presence of alkali. In another method a thionocarbamateester is rearranged to a thiol ester by reaction with an alkyl halide.The rearrangement is accompanied by transesterification. Still anothermethod is to condense a carbonyl halide with a mercaptan or mercaptide.

CIS- AND TRAN S-2,3-DICHLOROALLYL DIMETHYLTHIOLCARBAMATE A solutioncomprising 180 grams (1.0 mole) of 25% dimethylamine, 160 grams (1.0mole) of 25% sodium hydroxide and 1000 ml. of water was prepared andcarbonoxysulfide then bubbled in at 5 C. for 25 minutes or until therewas a gain in weight of 60.1 grams (1.0 mole). The reaction mixture wasstirred at 010 C. for one-half hour longer and the sodiumdimethylthiolcarbamate obtained as a 9.16% solution.

To 347.5 grams (0.25 mole) of the sodium dirnethylthiolcarbamatesolution so prepared there was added with stirring 36.2 grams (0.25mole) of cisand trans-1,2,3- trichloro-l-propene, the stirring continuedat 25 30 C.

for 24 hours, then the mixture heated at 50-60 C. for 3 hours. Aftercooling to 20 C. the reaction mixture was extracted with 300 ml. ofethyl ether, the ether solution washed with water until the washingswere neutral to litmus, dried over sodium sulfate, and the ether removedin vacuo at a maximum temperature of 90 C./12 mm. The cisandtrans-2,3-dichloroallyl dirnethylthiolcarbamate, an amber oil, wasobtained in 65% theory yield. Analysis gave 33.02% chlorine as comparedto 33.11% calculated for C H Cl NOS.

ALLYL DIMETHYLTHIOLCARBAMATE Employing a quantity of the same sodiumdimethylthiolcarbamate solution in the same proportion and under thesame reaction conditions but replacing the cisandtrans-1,2,3-tri-chloro-l-propene by 19.1 grams (0.25 mole) of allylchloride, allyl dimethylthiolcarbamate was obtained as an amber oil in60.6% yield. Analysis gave 9.50% nitrogen and 22.30% sulfur as comparedto 9.65% nitrogen and 22.07% sulfur calculated for C H NOS.

Z-CHLOROALLYL DIMETHYLTHIOLCARBAMATE In the same procedure and utilizinganother portion of the sames alkali metal thiolcarbamate, 27.8 grams(0.25 mole) of 2,3-dichloro-l-propene was substituted for the cisandtrans-1,2,3-trichloro-1-propene. The 2- chloroallyldimethylthiolcarbamate was obtained as an amber oil, B.P. 1121 14 C./4mm. Analysis gave 7.35% nitrogen and 18.11% sulfur as compared to 7.80%nitrogen and 17.84% sulfur calculated for C H CINOS.

The same compound was prepared from ethyl dimethylthionocarbamate. To133.2 grams (1.0 mole) of ethyl dimethylthionocarbamate was added withstirring grams (1.35 moles) of 2,3-dichloro-l-propene. The stirredreaction mixture was heated at 110-l150 C. for 48 hours and thendistilled to yield 2-chloroallyl dimethylthiolcarbamate, Bl. 1121l3 C./4mm., in 46.9% yield. Analysis gave 7.78% nitrogen and 17.68% sulfur ascompared to 7.80% nitrogen and 17.84% sulfur calculated for C H CI-NOS.

3,3-DICHLOROALLYL DIMETHYLTHIOL- CARBAMATE To a stirred solutioncomprising 180 grams 1.0 mole) of 25% dimethylamine, grams (1.0 mole) of25% sodium hydroxide, and 1000 ml. of water there was bubbled incarbonoxysulfide at 0-5 C. until there was a gain in weight of 75 grams(1.25 moles). The solution was stirred for an additional hour at roomtemperature and to this solution 145.3 grams (1.0 mole) of 1,1,3-trichloro-l-propene were added in one portion. Stirring was continuedfor 25 hours at room temperature and the reaction mixture extracted with500 ml. of ethyl ether. The ether solution was washed with water untilthe washings were neutral to litmus, dried over sodium sulfate, and theether removed in vacuo. Distillation of the reaction mixture under 4 mm.pressure gave an amber oil, B.P. 138140 C. The 3,3-dichloroallyldiniethylthiolcarbamate so obtained analyzed 6.54% nitrogen and 14.45%sulfur as compared to 6.54% nitrogen and 14.98% sulfur calculated for CH CI NOS.

3,3-DICHLO-ROALLY'L DIETHYLTHIOL- CAR-BAMATE A 12.7% aqueous solution ofsodium diethylthiolcarbamate was prepared by mixing 146.3 grams (2.0moles) of diethylamine, 320 grams (2.0 moles) of 25 sodium hydroxide,and 2000 ml. of water. To this solution, with stirring at 0 C., therewas bubbled in carbonoxysulfide until the gain in weight was 146 grams.The solution was stirred for an additional 2 hours at 0-5 C.

To 412.5 grams (0.33 mole) of the sodium diethylthiolcarbamate solutionso prepared there was added in one portion with stirring 36.4 grams(0.25) mole) of 1,1,3- trichloro-l-propene. The stirred mixture washeated at 50-60 C. for 3 hours and then maintained at 25-30 C.

for 12 hours. The product was extracted with 300 ml. of ethyl ether, theether solution washed with water until the washings were neutral tolitmus, and dried over sodium sulfate. The ether was removed in vacuo ata maximum temperature of 80 -90 C./1-2 mm. The 3,3-dichloroallyldiethylthiolcarbamate so obtained was an amber oil. Analysis gave 5.79%nitrogen, 13.28% Sulfur, and 29.95% chlorine as compared to 5.78%nitrogen, 13.24% sulfur, and 29.28% chlorine calculated for C H Cl NOS.

Employing a quantity of the same sodium diethylthiolcarbamate, thefollowing compounds were also prepared according to the procedure for3,3-dichloroallyl diethylthiolcarbamate:

ClS-AND TRANS-2,3-DICHLOROALLYL DIETHYLTHIOLCARBAMATE An amber oilanalyzing 5.59% nitrogen, 13.05% sulfur, and 29.61% chlorine as comparedto 5.78% nitrogen, 13.20% sulfur, and 29.20% chlorine calculated for C HCl NOS.

ALLYL DIETHYLTHIOLCARBAMATE An amber oil analyzing 8.03% nitrogen and18.43% sulfur as compared to 8.08% nitrogen and 18.50% sulfur calculatedfor C H NOS.

Z-BROMOALLYL D-IETHYLTHIOLCARBAMATE An amber oil analyzing 5.43%nitrogen and 31.40% bromine as compared to 5.54% nitrogen and 31.65%bromine calculated for CgHmBI'NOS.

Z-CHLOROALLYL DIETHYLTHIOLCARBAMATE of disclosure which do notconstitute departures from the spirit and scope of the invention.

What is claimed is:

1. The method of destroying parasitic worm life which comprisescontacting the said organism with a toxic concentration of athiolcarbarnate of the formula where R and R are alkyl of less thanthree carbon atoms and R" is selected from a group consisting of allyl,bromoallyl, and chloroallyl.

2. The method of claim 1 in which the parasitic worm life is nematodes,where R and R are alkyl of less than three carbon atoms, and R" isdichloroallyl.

3. The method of claim 1, where the parasitic worm life is nematodes inagricultural soils, R and R are methyl, and R" is 2-chloroallyl.

4. The method of claim 1 where the parasitic worm life is nematodes inagricultural soils, R and R are methyl, and R" is allyl.

5. The method of claim 1 where the parasitic worm life is nematodes inagricultural soils, R and R are ethyl, and R" is 2-bromoallyl.

6. The method of destroying parasitic worm life in agricultural soilswhich comprises contacting the said organism with a toxic concentrationof 2-chloroallyl dimethylthiolcarbamate.

References Cited UNITED STATES PATENTS 2,677,698 5/1954 Deutschman260-482 2,882,291 4/1959 Harman 167-22 2,895,980 7/1959 Harman 167-222,905,586 9/1959 Harman 167-22 2,943,972 7/1960 Meine Van Der Kerk167-22 2,990,319 5/1961 Jones 167-22 ALBERT T. MEYERS, Primary Examiner.

I. D. GOLDBERG, Assistant Examiner.

1. THE METHOD OF DESTROYING PARASTIC WORM LIFE WHICH COMPRISESCONTACTING THE SAID ORGANISM WITH A TOXIC CONCENTRATION OF ATHIOLCARBAMATE OF THE FORMULA